Method and electronic device for performing wireless charging

1. An electronic device comprising: a housing; a conductive coil; a power transmission circuit electrically connected to the conductive coil, and configured to wirelessly transmit power to an outside of the housing through the conductive coil; a voltage source electrically connected to the power transmission circuit; a sensing circuit electrically connected to the conductive coil; and a control circuit electrically connected to the power transmission circuit, the voltage source, and the sensing circuit, wherein the control circuit is configured to: control the power transmission circuit to transmit power through the conductive coil wirelessly, identify a frequency of a signal based on electromagnetic waves radiated through the conductive coil using the sensing circuit when the conductive coil transmits the power, and adjust a level of a voltage provided from the voltage source to the power transmission circuit based on the frequency of the signal and at least one threshold associated with the frequency of the signal, wherein the sensing circuit includes an inductor which is connected between the power transmission circuit and the conductive coil, wherein the control circuit comprises a switch electrically connected between the power transmission circuit and the voltage source, wherein the control circuit is further configured to adjust the switch to adjust the level of the voltage provided from the voltage source to the power transmission circuit, wherein the sensing circuit further comprises a capacitor having one end connected to an inverter for inverting power of a DC waveform to power of an alternating current (AC) waveform, and another end connected to a lumped inductor, wherein the switch has one end connected between the capacitor and the lumped inductor, and another end connected to the inverter, and wherein the switch is configured to output a voltage level adjusted based on a monitored result to the inverter.

2. The electronic device of claim 1 , wherein the control circuit is further configured to: identify whether the frequency is greater than or equal to a first threshold, and decrease the level of the voltage provided from the voltage source to the power transmission circuit, if the frequency is greater than or equal to the first threshold.

3. The electronic device of claim 2 , wherein the control circuit is further configured to: identify whether the frequency is less than or equal to the first threshold, and increase the level of the voltage provided from the voltage source to the power transmission circuit, if the frequency is less than or equal to the first threshold.

4. The electronic device of claim 1 , wherein the control circuit is further configured to: decrease the power from a first power level to a second power level less than the first power level, identify the frequency of the signal based on the electromagnetic waves radiated through the conductive coil shortly after or substantially simultaneously with the power decrease, identify whether the frequency is less than or equal to a first threshold, and further decrease the power from the second power level to a third power level less than the second power level based on a determination that the frequency is less than the first threshold.

5. The electronic device of claim 1 , wherein the control circuit is further configured to: decrease the power from a first power level to a second power level less than the first power level, identify the frequency of the signal based on the electromagnetic waves radiated through the conductive coil shortly after or substantially simultaneously with the power decrease, identify whether the frequency is greater than or equal to a first threshold, decrease the level of the voltage provided from the voltage source to the power transmission circuit, and further decrease the power from the second power level to a third power level less than the second power level.

6. The electronic device of claim 1 , wherein the control circuit is configured to identify whether the frequency of the signal is greater than or equal to a first threshold.

7. The electronic device of claim 1 , wherein one of the control circuit or the power transmission circuit is further configured to change the power radiated through the power transmission circuit to perform at least one of: adjusting a duty cycle of the signal based on the electromagnetic waves radiated through the conductive coil, or adjusting a duty of the signal based on the electromagnetic waves radiated through the conductive coil.

8. The electronic device of claim 1 , wherein the switch is a direct current (DC) to DC converter for adjusting the level of the voltage provided from the voltage source to the power transmission circuit and outputting the voltage at the adjusted level.

9. The electronic device of claim 1 , wherein one of the control circuit or the power transmission circuit is further configured to change the power radiated through the conductive coil by performing at least one operation, and wherein the at least one operation includes adjusting a duty cycle of the signal based on the electromagnetic waves radiated through the conductive coil.

10. A wireless charging method in an electronic device, the wireless charging method comprising: wirelessly transmitting power through a conductive coil using a power transmission circuit; identifying a transmission frequency of a signal radiated through the conductive coil by using a sensing circuit connected to the conductive coil when the conductive coil transmits the power; and adjusting the transmission frequency by adjusting a level of a voltage provided from a voltage source to the power transmission circuit based on a result of the identifying and at least one threshold associated with the transmission frequency of the signal, wherein the electronic device includes a switching module for adjusting the level of the voltage provided from the voltage source to the power transmission circuit, and the sensing circuit including a lumped inductor which is connected between the power transmission circuit and the conductive coil, and wherein the adjustment of the transmission frequency comprises adjusting the level of the voltage provided from the voltage source to the power transmission circuit by controlling the switching module.

11. The wireless charging method of claim 10 , wherein the adjustment of the transmission frequency comprises: identifying whether the transmission frequency is greater than or equal to a first threshold; and decreasing the voltage level, if the transmission frequency is greater than or equal to the first threshold.

12. The wireless charging method of claim 10 , wherein when the voltage level is decreased, the transmission frequency is decreased in correspondence to the decrease of the voltage level.

13. The wireless charging method of claim 10 , wherein the adjustment of the transmission frequency comprises: decreasing the voltage level from a first voltage level to a second voltage level less than the first voltage level; identifying whether the transmission frequency is less than a minimum threshold by monitoring the transmission frequency; and increasing the decreased voltage level, if the transmission frequency is less than the minimum threshold.

14. The wireless charging method of claim 10 , wherein the adjustment of the transmission frequency comprises: identifying whether the transmission frequency is less than a minimum threshold; and increasing the voltage level, if the transmission frequency is less than the minimum threshold.